Exploring the involvement of Na pump inhibitor marinobufagenin in the interactions between age-associated vascular and neurodegenerative processes in cognitive impairment and Alzheimer's disease

进行以下实验以检验研究假设： 我们使用雄性SD和DSS大鼠，其在整个实验中保持正常盐饮食（0.5%NaCl; n=8/组）。在3月龄和12月龄时进行纵向重复和非重复测量。使用以下组：DSS-3、DSS-12、SD-3和SD-12。在3月龄和12月龄时评估重复测量（收缩压，SBP;脉搏波速度，PWV，CAS指数;超声心动图）和非重复测量（Morris水迷宫，MWM，用于测试空间记忆;主动脉胶原蛋白、弹性蛋白（通过组织化学估计）和左心室（LV）纤维化、炎症和衰老相关基因的mRNA表达（qPCR）。采用线性混合效应双因素方差分析、t检验和线性回归（LR）模型进行数据分析。 我们已经证明，年轻的DSS-3与SD-3相比，SBP、PWV、主动脉重量、壁厚度和胶原蛋白/弹性蛋白比更高。DSS-12中的这些参数也高于DSS-3，而SD-12中仅PWV和主动脉壁厚度高于SD-3。DSS-12大鼠的相对左心室壁厚度（RWT）和促纤维化基因（胶原1a 2，1.5倍; TGF β 1，1.8倍）、炎症基因（TNFa 1，1.7倍）和衰老基因（GDF 15，3倍; TP 53，1.9倍）的LV表达高于DSS-3大鼠和DSS-12大鼠。DSS-12花费更多的时间在MWM中找到隐藏的平台，而SD-12（47 +/-3秒对27 +/-4秒; p<0.05）。LR分析显示，DSS-12的空间海马记忆受损与PWV和LV质量呈正相关。 根据本研究的结果，我们得出以下结论： （一） 伊娃（指数为较高的BP、PWV和主动脉重塑）与早期CV老化相关，表现为LV衰老、炎症和促纤维化基因的激活，以及DSS与SD相比，BP、RWT和LV质量的年龄相关变化率较高。 （二） 在DSS中，伊娃和早期CV老化与以后生活中的记忆力下降相关。 （三） DSS大鼠模型表现出与临床血管性痴呆的密切相似性，因为它们都存在高血压和CAS，这先于认知能力下降的发展。

The following experiment was performed to test the study hypotheses: We used male SD and DSS rats, which were kept on a normal salt diet (0.5% NaCl; n=8/group) for entire experiment. The longitudinal repeated and non-repeated measurements were performed at 3-mo and 12-mo of age. The following groups were used: DSS-3, DSS-12, SD-3 and SD-12. Repeated measurements (systolic blood pressure, SBP; pulse wave velocity, PWV, an index of CAS; echocardiography), and non-repeated measurements (Morris water maze, MWM, to test spatial memory; aortic collagen, elastin (estimated by histochemistry), and left ventricle (LV) mRNA expression (qPCR) of the genes related to fibrosis, inflammation and senescence) were assessed at 3-mo and 12-mo of age. Data analyses was performed using linear mixed-effect 2-way ANOVA, t-test and linear regression (LR) modeling. We have demonstrated, that SBP, PWV, aortic weight, wall thickness and collagen/elastin ratio were higher in young DSS-3 vs. SD-3. These parameters were also higher in DSS-12 vs. DSS-3, whereas only PWV and aortic wall thickness were higher in SD-12 vs. SD-3. Relative left ventricle wall thickness (RWT) and LV expression of pro-fibrotic genes (collagen1a2, 1.5-fold; TGFbeta1, 1.8-fold); inflammatory gene (TNFalpha1, 1.7-fold), and senescence genes (GDF15, 3-fold; TP53, 1.9-fold) were higher in DSS-12 vs. DSS-3 rats, and in DSS-12 vs. SD-12 rats. DSS-12 spent more time to find a hidden platform in MWM vs. SD-12 (47 +/-3 sec vs. 27 +/- 4 sec; p<0.05). Impaired spatial hippocampal memory in DSS-12 was positively associated with PWV and LV mass by LR analysis. Based on the results of this study we have concluded, that: (1) EVA, indexed as higher BP, PWV and aortic remodeling were associated with early CV aging, manifested by activation of LV senescence, inflammatory and pro-fibrotic genes and by higher rates of age-associated changes in BP, RWT and LV mass in DSS vs. SD. (2) In DSS, EVA and early CV aging was associated with memory decline later in life. (3) The DSS rat model exhibits close similarity to clinical vascular dementia by sharing the presence of hypertension and CAS, which precede cognitive decline development.